1. Field of the Invention
The present invention refers to an apparatus for taking photographs of an object in close proximity by means of a flash, especially an electronic flash.
2. Description of the Prior Art
Until now, when a photograph is taken by means of an electronic flash which gives an auxiliary illumination or flash light to the object, the adjustment is carried out in such a manner that the total light quantity peculiar to the electronic flash, i.e. the so-called guide number for ASA 100 corresponds to the product of the distance between the photographic camera and the object and of the aperture value of the diaphragm whereby the aperture of the diaphragm is variable. When photographing objects in close proximity, the distance between the photographic camera and the object is so small that the then proper exposure can not be obtained unless the aperture value should be adjusted below the lowest value adjustable on the diaphragm of the photographic camera. Accordingly it is impossible to take a photograph in close proximity in this way. Under such circumstances, the photograph is taken in such a manner that the light quantity of the electronic flash is reduced, the electronic flash being not directed to the object.
However, in the above mentioned way, it has been very difficult to always obtain a constant and proper exposure, because the proper exposure must be obtained only with great experience of the photographer or only after repeated trials and errors.
Further until now, when an electronic flash is used as the light for taking a photograph in close proximity, it has been impossible to obtain a uniform flash light, because the light distributing character of the electronic flash plays an important role for providing light to the object when the distance between the optical axis of the objectives of the photographic camera and the electronic flash becomes smaller in the direction of the object. Thus, as one of the counter-measures that has been carried out to provide light to the object in close proximity by means of an electronic flash consisting of a ring-shaped Xenon tube and being mounted on the objectives of the photographic camera. Nevertheless, even with such electronic flash, the above mentioned problems can not be solved. Moreover, when the object is in closer proximity, the object itself is provided with ring-shaped light by means of the light provided by the ring-shaped Xenon tube in such a manner that the center of the object is provided with less light. This can be considered another weak point.